Component pickup devices are important in the commercial production of electrical and optical systems. These devices must efficiently handle various electrical and optical components with precision and care.
Typical component pickup devices include a camera guided robotic arm with a vacuum pickup tool disposed at the working end of the arm. The vacuum pickup tool may include a collet that defines a sealing or pickup surface, and an orifice or passage which extends through the collet and couples to a vacuum source.
The components are typically supplied in bulk on a film or tape carrier for automatic handling by a component pickup device. The components are bonded to the carrier by an adhesive disposed on one side of the carrier. The components are removed from the carrier by the pickup device so that they may be placed, for example, on a circuit board.
A pin assembly is typically provided to assist removal of the components from the carrier. The adhesive force bonding the component to the film carrier is generally greater than the vacuum force exerted on the component by the pickup device. Consequently, a pin assembly is provided for lowering the adhesive force below that of the vacuum force. The pin assembly accomplishes this by pushing the component away from the film carrier prior to removal by the pickup device. With the adhesive force lowered below that of the vacuum force, the pickup tool can successfully lift the component from the carrier.
Unfortunately conventional pin assemblies can damage delicate components and their reliability is less than satisfactory. It has been found that the pressure applied by the pin assembly marks the component. Such marks often crack or damage the components, leading to component failure. Moreover, it is often difficult for the pin assembly to lift the component so that the planar surface of the component is kept parallel to the collet's pickup surface. The pin assembly often rotates or tilts the component slightly, causing the planar surface of the component to lie at an angle relative to the pickup surface of the collet. This causes camera vision problems which interfere with the robotic arm's ability to find the component on the film carrier. The tilting of the component may also prevent a vacuum seal at the planar surface/pickup surface interface. Consequently, the pickup tool is unable to repeatably remove all the components from the carrier.
Accordingly, there is a need for a method and apparatus which removes the components from the film carrier in a repeatable, damage-free manner.